The Nobel Prize in Physiology or Medicine 2012 was awarded to Prof. Shinya Yamanaka, who first created iPS cells, and Dr. John Gurdon, who studied the foundation of the above technology. It is expected that the iPS cells will bring a totally novel treatment strategy into pharmaceutical industries.
With regard to the iPS cell-related technology, Patent Literature 1, for example, discloses that introduction of four genes (Oct3/4, Klf4, Sox2, c-Myc) into a cell causes a pluripotent stem cell to be induced from the cell. In addition, with regard to a pluripotent stem cell-related technology, Patent Literature 2, for example, discloses that introduction of three genes (Oct3/4, Klf4, Sox2) and one miRNA (e.g., hsa-miR-372) into a cell causes a pluripotent stem cell to be generated. Further, Non-Patent Literature 1 describes that if the p53 gene is disrupted in a cell to be induced into a pluripotent stem cell when the above four or three genes are introduced, the pluripotent stem cell generation efficiency is increased. Furthermore, Patent Literatures 3 and 4 disclose that a pluripotent stem cell can be generated by introducing, into a cell, a specific RNA strand (e.g., miR-520d-5p).
Meanwhile, there is room for improvement in respect to the regulations of carcinogenesis and differentiation so as to apply iPS cells to clinical practice. Among the efforts, Patent Literature 5 shows the isolation of a cell fraction containing a Muse cell as a novel approach to pluripotent stem cells. This Patent Literature 5 discloses that the Muse cell shown in Patent Literature 5 can differentiate into any type of tissue, is useful as an iPS cell source (having a high efficiency of generating iPS cells), and can be isolated without introduction of any gene.